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postgresql/src/include/access/subtrans.h

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Nested transactions. There is still much left to do, especially on the performance front, but with feature freeze upon us I think it's time to drive a stake in the ground and say that this will be in 7.5. Alvaro Herrera, with some help from Tom Lane.
2004-07-01 02:52:04 +02:00
/*
* subtrans.h
*
* PostgreSQL subtrans-log manager
*
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
Tweak code so that pg_subtrans is never consulted for XIDs older than RecentXmin (== MyProc->xmin). This ensures that it will be safe to truncate pg_subtrans at RecentGlobalXmin, which should largely eliminate any fear of bloat. Along the way, eliminate SubTransXidsHaveCommonAncestor, which isn't really needed and could not give a trustworthy result anyway under the lookback restriction. In an unrelated but nearby change, #ifdef out GetUndoRecPtr, which has been dead code since 2001 and seems unlikely to ever be resurrected.
2004-08-22 04:41:58 +02:00
* $PostgreSQL: pgsql/src/include/access/subtrans.h,v 1.2 2004/08/22 02:41:58 tgl Exp $
Nested transactions. There is still much left to do, especially on the performance front, but with feature freeze upon us I think it's time to drive a stake in the ground and say that this will be in 7.5. Alvaro Herrera, with some help from Tom Lane.
2004-07-01 02:52:04 +02:00
*/
#ifndef SUBTRANS_H
#define SUBTRANS_H
#include "access/xlog.h"
/* exported because lwlock.c needs it */
/* cannot be different from NUM_CLOG_BUFFERS without slru.c changes */
#define NUM_SUBTRANS_BUFFERS NUM_CLOG_BUFFERS
extern void SubTransSetParent(TransactionId xid, TransactionId parent);
extern TransactionId SubTransGetParent(TransactionId xid);
extern TransactionId SubTransGetTopmostTransaction(TransactionId xid);
extern int SUBTRANSShmemSize(void);
extern void SUBTRANSShmemInit(void);
extern void BootStrapSUBTRANS(void);
extern void StartupSUBTRANS(void);
extern void ShutdownSUBTRANS(void);
extern void CheckPointSUBTRANS(void);
extern void ExtendSUBTRANS(TransactionId newestXact);
extern void TruncateSUBTRANS(TransactionId oldestXact);
extern void subtrans_zeropage_redo(int pageno);
#endif /* SUBTRANS_H */